BOISE - A 1988 Nobel Prize put up for auction by a retired experimental physicist now facing memory loss and potential medical bills has sold for $765,002.

The online auction went into overtime Thursday evening until a final bid went unchallenged for half an hour in the competition for the gold medal won by Leon Lederman.

"I'm shocked it sold at all," said his wife, Ellen Lederman, on Friday. "We would let little kids play with it and have their picture taken."

She said Friday that her husband, 92, is otherwise healthy, and they are financially comfortable in retirement, but that they now face potential costly medical bills and uncertainty following a dementia diagnosis for the Nobel Prize winner.

"It's terrible," she said. "It's really hard. I wish it could be different. But he's happy. He likes where he lives with cats and dogs and horses. He doesn't have any problems with anxiety, and that makes me glad that he's so content."

They hadn't thought about selling the Nobel Prize until being contacted by Los Angeles-based Nate D. Sanders Auctions about a month ago, she said.

Lederman won the Nobel Prize in physics with two other scientists for discovering a subatomic particle called the muon neutrino. He used the prize money to buy a log cabin near the tiny town of Driggs in eastern Idaho as a vacation retreat.

He retired from Fermi National Accelerator Laboratory in Batavia, Ill., near Chicago in June 2012 and moved to Idaho full time. In an interview with The Associated Press on Tuesday, he said he couldn't remember the work that went into winning the Nobel Prize.

"I don't have any real stories to tell about it," he said, noting the prize had been sitting on a shelf for 20 years. "I sit on my deck and look at the mountains."

Nate D. Sanders Auctions said the final amount for Lederman's medal is the fourth-highest ever paid among the 10 Nobel Prizes that have been sold at auction, and only the second to be put up for auction by a living Nobel Prize winner.

"I think it's above all the awards as most interesting and prestigious a person can get," company spokeswoman Laura Yntema said. "We're very happy for the Ledermans. We're just very pleased that we were able to get a good price for their Nobel Prize."

The company declined to identify the buyer, who declined a request through the company to be interviewed.

The company, which specializes in selling entertainment and sports awards, said Lederman's award received the second highest selling price in the company's history. The highest was $861,542 paid in 2011 for the Oscar won by Orson Wells in 1941 for Best Original Screenplay for the movie "Citizen Kane."

Leon Lederman parlayed his Nobel Prize and enthusiasm for physics to spread his love for science in all kinds of venues, even setting up a makeshift table on sidewalks in New York and Chicago so passers-by could ask a Nobel laureate a question. People stood in line to do so.

He also wrote books and is generally identified as coming up with the term the "God particle," a layman-friendly name for a subatomic particle otherwise called the Higgs boson.

Besides the Nobel Prize, he won numerous other prestigious awards such as the Wolf Prize in Physics and the U.S. National Medal of Science, but which are not much recognized among the general population.

"All this stuff to the public is just kind of fluff," said Ellen Lederman, 67. "The Nobel is something that people are really aware of."